Governing mechanism for turbines.



No. 861,085. PATENTED JULY 28, 1907.

- J. G. GALLAN:

GOVERNING MECHANISM FOR TURBINES.

APPLICATION FILED JAIL 2. 1906.

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No. 861,085. PATENTED JULY 23, 1907. J. GALLAN: GOVERNING MECHANISM FORTURBINES.

APPLICATION FILED JAN. 2. 1906.

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JOHN G. CALLAN, OF LYNN,

MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC- COMPANY,

A CORPORATION OF NEW YORK.

GOVERNING MECHANISM FOR TURBINES.

Specification of Letters Patent.

PatentedJ 1113 23, 1907.

Application filed January 2,1906. Serial No- 294,162.

To all whom it may concern:

Be it known that I, JOHN G. OALLAN, a citizen of the United States,residing at Lynn, county of Essex, State of Massachusetts, have inventedcertain new and useful Improvements in Governing Mechanism for Elastic-Fluid Turbines, of which the following is a specification.

The present invention relates to mechanisms for governing the passage ofmotive fluid from one stage to another in a multi-stage turbine, and hasfor its object to improve their construction.

In the accompanying drawings, which are illustrative of one embodimentof the invention, Figure 1 is a partial section of a multi-stageturbine, the section be-- ing taken on line l1 of Fig. 2; Fig. 2 is apartial plan and sectional view of the same, the section being taken online 22 of Fig. 1; Fig. 3 is a detail view of a baffler to prevent thestage-valves from opening too rapidly;

Fig. 4 is a detail view of an admission-valve and its actuatingcross-head; Fig. 5 is a diagrammatic view of a speed-responsive deviceas applied to a turbine fitted with my improved valve mechanism, andFig. 6 is a view showing a cross-head for operating the stage valve. 1represents the casing of the turbine which is divided by diaphragms 2into two or more stages. Instead of the arrangement shown, each stagemay be contained in a separate casing, and the casings connected orarranged in any desired manner.

Mounted on the casing is a head 3 having one or more openings to receivethe lower end of the valve chest 4 and the nozzles 5, or other fluiddischarging devices,

which may be expanding or non-expanding in character. In each stage ismounted a wheel 6 having one or more rows of wheel buckets 7. When twoor more rows of buckets are provided for each stage, a row more or lesscomplete of stationary intermediate buckets 8 is arranged between eachtwo rows of wheel buckets. The casing is connected to atmospheric orcondenser exhaust in the usual manner.

The casing is provided with an internal shoulder 9 that supports theupper diaphragm, and in this shoulder are cored passages 10 and 11, theformer leading from the first stage and the latter communicating withthe second stage-nozzles 12, of which there may be one, two or more. Itis to be understood that there are or may be other stage-nozzles whichare normally open and are not controlled by automatic stage-valves. Thepassages 10 and 11 terminate in a valve casing 13 which is preferablybut not necessarily bolted to the periphcry of the wheel casing. Thevalve casing is provided with a partition 14 supporting a valve seat 15.The

space above the valve 16 and the partition is connected to the firststage by the passage 10, while that below is connected to the secondstage-nozzles by the passage 11. The lower end of the valve stem 17 isprovided with a piston 18 of less diameter than the valve and located inthe cylinder 19, the latter being removable and held in place by thedetachable head 20.

It is 'to be observed that although the piston 18 is smaller in diameterthan the valve, it is subjected, under the control of the governor, to asuperior pressure by reason of the fact that live steam is admitted tothe cylinder 19 whereas the pressure above the valve is that due to thesteam after it has passed through the first stage-nozzles or otherdevices and wheel. The clearance between the lower surface of the piston18 and the cylinder head should be small so as to prevent too rapidopening of the stage-valve when elastic fluid is used as the motivepower medium.

It may be here stated that some other fluid, such as water, oil or air,may be used to actuate the stage-valve or valves. The upper end of thecylinder is provided with an inturned flange 21 that acts as a stop tolimit the upward movement of the piston and valve. The upper end of thevalve stem is provided with a piston 22 freely moving in a cylinder 23formed on the upper head 24 and acts as a dash-pot. Steam or otherfluid, elastic or non-elastic, is admitted by the pipe 25 to the underside of the lower piston 18 when it is desired to raise the valve, andis exhausted therefrom when it is desired to close the valve as will bedescribed later.

Steam or other elastic fluid is admitted to the valve chest 4 by asuitable conduit, Fig. 5, and the passage of fluid from the chest to thenozzles or other fluid discharging devices 5 is controlled by aplurality of separately actuated valves 26. "he-admission-valves aresuccessively actuated both in opening and in closing, and have an openposition and a closed position but no intermediate. The mechanism foractuating the admission-valves is the same as that employed to actuatethe pilot or relay-valves so the description will be chiefly directedthereto.

Situated above the valve chest 4 is a frame 27, and mounted therein areas many cross-heads 28 as there are admission-valves to be controlled.In this case certain of the cross heads will actuate the pilot valvesand also the nozzle valves. Instead of this arrangement, the pilotvalves may have separate cross-heads of the character shown and actuatedin the same manner. If desired, however, one cross-head may control twoor more stage-valves, as for example Where the succeeding stages oflower pressure after the second are valved, or where it is desired ,tosimultaneously open two or more stage-valves in the same stage. Wherethe cross-heads are employed to actuate admission-valves they aredirectly connected to their stems 29, Fig. 4,

' pressure and not the initial pressure.

haust.

and where employed to control stage-valves, to the stems 30 of thepilot-valves.

In Fig. 6 is shown a separate cross-head for actuating a pilot valve.Between the stem and the cross-head is interposed a coiled compressionspring 31 contained in a head 32. At the upper end of the frame 27 areas many cylinders 33 as there are pilot-valves 34, the latter being ofsuitable form, as for example of the piston type. To the cylinder, andat a point below the pilotvalve, is connected a pipe 35 leading to asource of supply. It may be connected to a separate source of sup ply,to the valvechest direct, as by a pipe 36, or to one of the passages 37leading to one, two or more nozzle sections. The latter arrangement isthe one shown, and it is to be understood that the parts are so relatedthat the nozzle valve 26 is opened before the cross-head moves thepilot-valve to a position to admit steam to the cylinder 19. To statethe matter in other words, the stage-valves are directly under thecontrol of the governor and operate between the opening and closing ofthe admission-valves, not simultaneously therewith. By taking steam foroperating a stage-valve from the pipe 36, an admission and a stage-valvemay open or close simultaneously, but the opening or closingof astage-valve is not in any sense under the control of an admission-valve,but is under the control of the speedgovernor.

One advantage of the construction shown resides in the fact that uponsuch a decrease in load as will close the nozzle or admission-valve 26the pressure in the pipe 35 and the conduits connected therewith will bematerially reduced because it then becomes the stage To the centralportion of the casing of the pilot-valve is connected the pipe 25leading to the cylinder of the motor for actuating the stage-valve. Theupper end of the cylinder is connected by thepipe 38 to atmospheric orother eX- Ipreier to connect the pipe to a condenser in order to obtainthe benefit of the latter when it is desiredito lower the piston 18 andclose the stage-valve.

Mounted on the frame 27 are as many actuators 39 as there arecross-heads. These actuators are carried in a suitable frame supportedby the spindle 40, and

' are kept constantly moving to and fro by the lever 41 through suitablemeans driven by the turbine shaft or by separate means. Pivotallymounted on each of the I actuators are dogs 42 and 43 which at all timestend to engage with the shoulders 44 and 45 on the cross-head by reasonof the spring 46. The action of each pair of dogs is controlled by ashield plate 47, the latter being loosely mounted on the spindle 40 andconnected to the speed governor by a rod 48 so that as the speed of theturbine varies the number of valves in service will be changed to suitthe requirements. The shieldplates for the several cross-heads areconnected together and set angularly one behind the other by a slightamount so as to cause successive operation of the admission andstage-valves. By suitably proportioning the width of the active face ofeach shield-plate to the dogs, each valve may, with the shield in acentral position, be opened and closed once for each complete movementof an actuator 39. This arrangement has the advantage of reducing thenumber of admissionvalves required. The regulating-valve will then openand close with a definite periodicity and the period will be unvarying.

In Fig. 2 is shown two stage-valves arranged for successive operation,but I may use only one valve or a number greater than two and operatethem successively. The valves may beused in one stage only or in'two ormore stages as best suit the requirements. I have described theadmission-valves as being mechanically operated and the stage-valves asbeing operated by fluid under pressure, but it is to be understood thatI may under certain conditions operate admissionvalves in a mannersimilar to the stage-valves if desired.

The operation of the mechanism on increasing load, assuming that some ofthe admission-valves are open and the pressure above the stage-valvegreater than that below it, is as follows Assuming a change in load, thespeed governor adjusts a shield-plate 47 so that the next upward strokeof the actuator 39 causes the upper dog to engage the shoulder 44 andraise the cross-head 28 and pilot-valve 34. "This will permit steam toflow from the passage 37 (it being understood-that the admission-valve26 has been previously opened), or from pipe 36 to pipe 35, cylinder 33,thence to pipe 25 and cylinder 19. The fluid thus admitted to thecylinder overcomes the pressure on the upper side of the stagevalve 16and the latter rises and permits steam to pass freely from passage 10 topassage 11, thence to the sec- 0nd stage nozzles 12, or to the nozzlesof any other stage if desired. It is to be noted that when thestagevalve 16 is open, the pressure in the passage 11 is higher thanwhen the valve is closed because in the former case it is equal to thatin the first stage and in the latter case to the pressure in the secondstage, be-

cause of the nozzles 12 open thereto. This action increases the torqueof the turbine, due to the admission of more steam to the first stageand also to the second and succeeding stages. The dash-pot piston 22 isloosely fitted into its cylinder so that when in the position shown inFig. 1, the pressures above and below it are the same or substantiallyso. On a decrease in load accompanied by an increase in speed thegovernor moves a shield-plate 47 to'a position where it permits thelower dog to engage the shoulder 45 on its next downward stroke andlower the crosshead and pilot valve. This cuts off steam from the pipe25 and opens it and the cylinder 19 to the condenser exhaust whichquickly causes the piston 18 to drop and close the stage valve owing tothe stage pressure in passage 11 which unbalances the pressures on thepiston. A greater increase in load will open the remaining admission andstage-valves one after the other and a greater decrease in load willclose the admission and stagevalves one after the other. I

In Fig. 3 is shown a batfler for preventing the stagevalves from openingtoo rapidly by retarding the flow of fluid, and preferably is located asnear the cylinder 19 as possible. It comprises ashell 50 having a boreof two different diameters, one forming a chamber 51, the other closelyfitting the screw-threaded removable plug 52.- Located in the chamberand surrounding the plug is a strainer 53 made of gauze and a cylinder54 made of perforated metal. Steam or other fluid, elastic or nonelastic is admitted to the shell by the passage 55, and leaves it by thespiral passage formed in the plug. In

some cases it will be necessary to use both the dash-pot and baffier andin other cases only one of them. Instead of using the specific form ofleather shown, I may use other forms.

In Fig. 4 is shown a nozzle-valve 26 connected by its stem 29 with across-head 28 the latter being moved to and fro by dogs similar inconstruction and operation to those previously described. I

In Fig. is shown a speed-responsive device 57 that is connected to therod 48 which moves the shield plates by the lever 58. The lever 41 thatmoves the actuators 39 back and forth is driven by a crank 59 which inturn is driven by the main shaft of the turbine through suitablespeed-reducing gearing.

It will be seen that the admission-valves are mechanically andpositively opened and closed, while the stage-valves are opened andclosed by fluid-actuated motors in response to speed changes, the samespeed governor being employed to control both sets of valves.

This arrangement is simpler, costs lessand requires fewer parts thanwhere both admission and stage-valves are mechanically operated. It isalso less difiicult to install and take down, and the stage-valves canbe located at whatever point or points on the turbine are mostconvenient. If anything happens to a stage-valve it can be disconnectedand the remainder of the apparatus will operate as before.

While I have shown the pilot-valves operated and controlled bycrossheads, actuators, dogs, shieldplates, etc., my invention is not tobe considered as being limited thereto except as specifically referredto in the claims.

It is evident that my invention can be used in connection with any formof admission valve or valves, and this whether the valve or valves is orare arranged to open and close with or without throttling.

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof;but I desire to have it understood that the apparatus shown is onlyillustrative, and that the invention can be carried out by other means.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is,-

1. In a governing mechanism for multi-stage turbines, the combination ofan admission valve, means tor actuating the admission valve, astage-valve, means for actuating the stagevalve, and a speed-responsivedevice which acts on the stage valve to open it subsequent to acting onthe admission valve and prior to acting on said admission valve to closeit.

2. In a governing mechanism for mnlti-stage turbines,

the combination of a plurality of admission-valves, means under thecontrol of a speed governor for actuating the admission valves, aplurality of stage valves, means under the control of the speed governorfor actuating the stagevalves, and a speed governor which acts on thestagevalves successively and between the periods when it acts on theadmission-valves.

3. In a governing mechanism for multi-stage turbines, the combination ofa device moved by a speed governor, an admission valve under the controlof said device, a stage valve, a fluidactuated motor for controlling thestagevalve, the diameter of the valve being greater than that of themotor piston, and a pilot-valve for controlling the stage-valve that isconnected to the device operated by the speed governor.

4. In a governing mechanism for multi-stage turbines, the combination ofadmission and stage-valves, a mechanical means for opening and closingthe admission-valves, a fluid-pressure means for actuating thestage-valve or valves, and a speed-responsive device that is common toand controls the operation of the valves.

5. In a governing mechanism for multi-stage turbines, the combination'ofadmission and stage-valves, a mechanical means for opening and closingthe admission-valves, a fluid-pressure means for actuating the stagevalve or valves, one or more pilot valves for controlling the action ofthe stage-valve-or valves, and a speed-responsive device that is commonto said mechanical means and the pilotvalve or valves.

6. In a governing mechanism for multi-stage turbines, the combination ofadmission-valves, cross-heads connected to the valve stems, actuatorsfor moving the cross-heads to and fro, one or more stage-valves,fluid-pressure motors for actuating them, one or more cross-heads forthe stage.

valves, one or more actuators for moving the last-mentioned cross-headsto and fro, one or more pilot valves for the motors actuated by thecross-head or heads, and a speed-responsive device which controls theaction of the admission-valve actuators and the pilot-valves.

7. In a governing mechanism for multi-stage turbines, the combination ofa plurality of separately actuated admission valves, one or morestage-valves, one or more fluid-pressure motors for actuating thestage-valves, a baffiing device in the conduit between the source ofsupply and a motor, and a speed-responsive device for controlling theadmission of motive fluid to the turbine. l

8. In a governing mechanism for multi-stage turbines, the combination ofa plurality of separately actuated admission-valves, one or more stagevalves, one or more fluidpressure motors for actuating the stage-valves,one or more dash-pots for damping.the action of the stage-valve orvalves, and a speed-responsive device for directly controlling theaction of the admission and stage valves.

9. In a governing mechanism for multi-stage turbines, the combination ofa speed-governor, a stage valve, a fluid actuated motor for opening andclosing the stage valve, a conduit for admitting high pressure fluid tothe motor, and a pilot valve moved by the governor for regulating thepassage of fluid through the conduit to the motor.

In witness whereof, I have hereunto set my hand this twenty-ninth day ofDecember, 1905.

' JOHN G. CALLAN.

Witnesses ALEX. F. MACDONALD, JOHN A. MCMANUS, Jr.

